A nanoparticle conjugate includes a quantum dot (QD) and a thermally activated delayed fluorescence (TADF) molecule bound to the QD. In some instances, the TADF molecule can be directly bound to a surface of the QD. In other instances, the TADF molecule can be indirectly bound to the QD via an interaction with one or more capping ligands disposed on a surface of the QD. Nanoparticle conjugates described herein can be incorporated into emissive layers of electroluminescent light-emitting diode devices to yield electroluminescent quantum dot-containing light-emitting diode (QD-LED) devices.